HMS87C4260 데이터 시트보기 (PDF) - Hynix Semiconductor

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HMS87C4260

8-BIT SINGLE-CHIP MICROCONTROLLERS

Hynix Semiconductor 

HMS81C4x60

8.2 Program Memory

A 16-bit program counter is capable of addressing up to

64K bytes, but this device has 60K bytes program memory

space only physically implemented. Accessing a location

above FFFFH will cause a wrap-around to 0000H.

Figure 8-5 shows a map of Program Memory. After reset,

the CPU begins execution from reset vector which is stored

in address FFFEH and FFFFH as shown in Figure 8-6.

As shown in Figure 8-5, each area is assigned a fixed loca-

tion in Program Memory. Program Memory area contains

the user program.

1000H

Example: Usage of TCALL

LDA

#5

TCALL 15

:

:

;

;TABLE CALL ROUTINE

;

FUNC_A: LDA LRG0

RET

;

FUNC_B: LDA LRG1 2

RET

;

;TABLE CALL ADD. AREA

;

ORG 0FFC0H

DW FUNC_A

DW FUNC_B

;1BYTE INSTRUCTION

;INSTEAD OF 2 BYTES

;NORMAL CALL

1

;TCALL ADDRESS AREA

FEFFH

FF00H

FFC0H

FFDFH

FFE0H

FFFFH

TCALL

AREA

INTERRUPT

VECTOR AREA

PROGRAM

MEMORY

PCALL

AREA

Figure 8-5 Program Memory Map

Page Call (PCALL) area contains subroutine program to

reduce program byte length by using 2 bytes PCALL in-

stead of 3 bytes CALL instruction. If it is frequently called,

it is more useful to save program byte length.

Table Call (TCALL) causes the CPU to jump to each

TCALL address, where it commences the execution of the

service routine. The Table Call service area spaces 2-byte

for every TCALL: 0FFC0H for TCALL15, 0FFC2H for

TCALL14, etc., as shown in Figure 8-7.

The interrupt causes the CPU to jump to specific location,

where it commences the execution of the service routine.

The External interrupt 1, for example, is assigned to loca-

tion 0FFF8H. The interrupt service locations spaces 2-byte

interval: 0FFF6H and 0FFF7H for External Interrupt 2,

0FFE8H and 0FFE9H for External Interrupt 3, etc.

Any area from 0FF00H to 0FFFFH, if it is not going to be

used, its service location is available as general purpose

Program Memory.

Address

0FFE0H

E2

E4

E6

E8

EA

EC

EE

F0

F2

F4

F6

F8

FA

FC

FE

Vector Area Memory

I2C Bus Interface Interrupt Vector

-

Basic Interval Timer Interrupt Vector

Watchdog Timer Interrupt Vector

External Interrupt 3/4 Vector

Timer/Counter 3 Interrupt Vector

Timer/Counter 1 Interrupt Vector

V-Sync Interrupt Vector

Slicer Interrupt Vector

Timer/Counter 2 Interrupt Vector

Timer/Counter 0 Interrupt Vector

External Interrupt 2 Vector

External Interrupt 1 Vector

On Screen Display Interrupt Vector

-

RESET Vector

NOTE:

"-" means reserved area.

Figure 8-6 Interrupt Vector Area

November 2001 Ver 1.1

23

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